With increasing development of an inkjet technology, the inkjet technology is not only used in the traditional printer market but also used in flat panel displays and semiconductor manufacturing processes in recent years. However, for reducing the fabricating cost and saving the process time, researchers are seeking new inkjet technologies. As known, a piezoelectric inkjet technology is one of the most widely-used new inkjet technologies.
Conventionally, the piezoelectric inkjet head structure comprises a nozzle plate, a cover plate and a piezoelectric actuating module. Please refer to FIGS. 1A and 1B. The conventional piezoelectric actuating module 1 comprises an upper piezoelectric chip 11, a lower piezoelectric chip 12, and two electrodes 13 and 14. The electrode 13 is disposed on the upper piezoelectric chip 11. The electrode 14 is disposed on the lower piezoelectric chip 12. In addition, a conductive layer 15 is arranged between the two electrodes 13 and 14. For example, the conductive layer 15 is a conductive adhesive for connecting the two electrodes 13 and 14 with each other. The conventional piezoelectric actuating module 1 further comprises a plurality of flow channels 16a, 16b and 16c. These flow channels 16a, 16b and 16c extend downwardly from the upper piezoelectric chip 11 to the lower piezoelectric chip 12. The entrances 161 of these flow channels are all located at the upper piezoelectric chip 11.
Please refer to FIG. 1B, which schematically illustrates the actions of the conventional piezoelectric actuating module. During operation of the piezoelectric actuating module 1, the electrodes 13 and 14 generate an electric field. According to the positive and negative voltages, the electric field causes deformation of the upper piezoelectric chip 11 and the lower piezoelectric chip 12. As shown in FIG. 1B, when opposite voltages are applied on both sides of the upper piezoelectric chip 11 and the lower piezoelectric chip 12, the flow channel 16b is expanded. As the flow channel 16b is expanded, the flow channels 16a and 16c at bilateral sides of the flow channel 16b are compressed. Consequently, the ink liquid (not shown) contained in the flow channels 16a and 16c will be ejected out through a nozzle (not shown). Moreover, since the flow channel 16b is expanded, the ink liquid (not shown) will be introduced into the flow channel 16b. By alternately changing the positive and negative voltages, the ink liquid can be ejected out through different flow channels 16 and corresponding nozzles (not shown).
In the conventional piezoelectric actuating module 1 as shown in FIGS. 1A and 1B, the flow channels 16a, 16b and 16c are extended downwardly from the upper piezoelectric chip 11 to the lower piezoelectric chip 12, and the entrances 161 of these flow channels are all located at the upper piezoelectric chip 11. Consequently, the base part 121 between every two adjacent ones of the flow channels 16a, 16b and 16c is relatively weak. Since the flow channels 16a, 16b and 16c are expanded or compressed during the operations of the conventional piezoelectric actuating module 1, the base parts 121 beside the flow channels 16a, 16b and 16c are adversely affected. Since the base parts 121 are frequently subject to deformation and compression, the base parts 121 are readily damaged. Under this circumstance, the performance of the conventional piezoelectric actuating module 1 is deteriorated, and thus the piezoelectric inkjet head structure is possibly damaged.
Therefore, there is a need of providing a piezoelectric inkjet head structure with a strong structural strength so as to minimize the damaging possibility.